Cleaner shrimp really do little for ich, but might pick off some of the parasites...they more pick off pieces of loose skin, and such than they do parasites. Not to say that that they can't help with an ich infestation, but certainly not the answer either...They probably won't get any of the parasites in the gills, (those are the ones that do the most harm) , nor the ones that are deeply in the skin tissue...Here's some info on them:
"there are also several kinds of shrimps that make a living by picking off and eating parasites, dead skin, and other materials found on "dirty" fishes. These "cleaner shrimps" have some sort of coloration and/or behavior that lets fishes know that they can get a free cleaning if they’ll be nice enough not to make a meal of the cleaner. So, cooperative fishes will come to a shrimp and sit still, or move around slowly, and will let the shrimp go over their body and pick them clean. Sometimes big fishes will even open up and let a cleaner shrimp crawl inside their mouths and pick their teeth and gills clean as well. Obviously, this is a very beneficial service as it is hard to imagine a fish passing up such an easy meal without a good reason.
Unfortunately, sometimes these same shrimps don’t seem to want to do their job in an aquarium, though. I don’t know why, but many times cleaner shrimps just won’t clean. It doesn’t seem to have anything to do with the fishes in the aquarium either."
